The present invention relates generally to the field of waveguides and, more specifically, to waveguide filter elements. Conventional waveguide filters use elements that are in electrical and mechanical contact with the waveguide walls. Typical examples of these types of filters include inductive posts and inductive irises. These reactive elements are realized by means of metal rods or plates that are inserted into carefully machined openings and bonded to the walls of the waveguide by means of soldering, welding or compression techniques. Newer printed circuit waveguide filters also use such elements that are printed on substrates that are held suspended between the waveguide walls with firm metallic contacts at the walls. These filters, known as fin-line filters are simpler to make than irises and inductive posts but also require very precise machining to split the waveguide and cut the groove for supporting the substrate. Because the foregoing described type of filter elements are in contact with the waveguide walls and because currents flow in the junctions between the elements and the waveguide walls, and because of junction imperfections, the filter loss and reflection quality are often degraded.